@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:ital,wght@0,400;0,500;0,700;1,400&display=swap');

/* ===== 基础重置 ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background: #fdfbf7;
  color: #1a1a1a;
}

body {
  font-family: 'Plus Jakarta Sans', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  font-size: 1rem;
  line-height: 1.7;
  background: #fdfbf7;
  color: #1a1a1a;
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
}

/* ===== 纸质肌理 ===== */
.paper-texture {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: 0.035;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='300' height='300'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.75' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='300' height='300' filter='url(%23n)' opacity='1'/%3E%3C/svg%3E");
  background-repeat: repeat;
  background-size: 300px 300px;
}

/* ===== 站头 ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: #fdfbf7;
  border-bottom: 1px solid #1a1a1a;
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.site-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  height: 60px;
}

.nav-left,
.nav-right {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  list-style: none;
  padding: 0;
  flex: 1;
}

.nav-right {
  justify-content: flex-end;
}

.nav-left li a,
.nav-right li a {
  display: inline-block;
  padding: 0.55rem 0.6rem;
  font-size: 0.8rem;
  font-weight: 500;
  color: #1a1a1a;
  text-decoration: none;
  letter-spacing: 0.02em;
  border-radius: 4px;
  transition: none;
  white-space: nowrap;
  min-height: 40px;
  line-height: 1.2;
  display: flex;
  align-items: center;
}

.nav-left li a:hover,
.nav-right li a:hover {
  background: #f5f5f5;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.nav-cta {
  background: #1a1a1a !important;
  color: #fdfbf7 !important;
  border-radius: 4px !important;
  font-weight: 700 !important;
  padding: 0.55rem 1rem !important;
}

.nav-cta:hover {
  background: #333 !important;
}

.brand-center {
  flex-shrink: 0;
  text-align: center;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: #1a1a1a;
}

.brand-name {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  white-space: nowrap;
}

.brand-logo-img {
  height: 28px;
  width: auto;
}

/* ===== Hero ===== */
.hero-section {
  position: relative;
  min-height: 70vh;
  display: flex;
  align-items: center;
  justify-content: center;
  border-bottom: 1px solid #1a1a1a;
  overflow: hidden;
  scroll-margin-top: 60px;
}

.hero-bg-text {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: clamp(6rem, 20vw, 16rem);
  font-weight: 700;
  color: #f5f5f5;
  letter-spacing: 0.15em;
  pointer-events: none;
  user-select: none;
  white-space: nowrap;
  z-index: 0;
}

.hero-inner {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 4rem 2rem;
  gap: 1.5rem;
  max-width: 700px;
}

.hero-icon {
  opacity: 0.85;
}

.hero-h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: #1a1a1a;
}

.hero-sub {
  font-size: 1.05rem;
  line-height: 1.7;
  color: #444;
  max-width: 520px;
}

.hero-btn {
  display: inline-block;
  padding: 0.75rem 2rem;
  background: #1a1a1a;
  color: #fdfbf7;
  font-size: 0.95rem;
  font-weight: 700;
  text-decoration: none;
  border-radius: 4px;
  letter-spacing: 0.04em;
  min-height: 44px;
  line-height: 1;
  display: inline-flex;
  align-items: center;
}

.hero-btn:hover {
  background: #333;
}

/* ===== 主内容区 ===== */
.site-main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 3rem 1.5rem 4rem;
}

.wrap {
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: 2.5rem;
  align-items: start;
}

.content-section {
  min-width: 0;
}

.content-article {
  min-width: 0;
}

.content-body {
  font-size: 1rem;
  line-height: 1.8;
  color: #1a1a1a;
}

/* 正文内容样式 */
.content-body h2 {
  font-size: 1.4rem;
  font-weight: 700;
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid #1a1a1a;
  letter-spacing: -0.01em;
}

.content-body h2:first-child {
  margin-top: 0;
}

.content-body h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin: 1.8rem 0 0.7rem;
}

.content-body p {
  margin-bottom: 1rem;
}

.content-body ul,
.content-body ol {
  margin: 0.8rem 0 1rem 1.5rem;
}

.content-body li {
  margin-bottom: 0.4rem;
}

.content-body a {
  color: #1a1a1a;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.content-body a:hover {
  opacity: 0.7;
}

.content-body strong {
  font-weight: 700;
}

.content-body blockquote {
  margin: 1.5rem 0;
  padding: 1rem 1.25rem;
  border-left: 3px solid #1a1a1a;
  background: #f5f5f5;
  font-style: italic;
}

.content-body section {
  scroll-margin-top: 70px;
  padding-top: 0.5rem;
}

.content-body img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 1.5rem 0;
  border: 1px solid #e0e0e0;
}

/* ===== 侧边栏 ===== */
.content-aside {
  position: sticky;
  top: 75px;
  background: #f5f5f5;
  border: 1px solid #1a1a1a;
  border-radius: 10px;
  padding: 1.5rem;
  min-width: 0;
}

.aside-inner {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.aside-title {
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #1a1a1a;
  border-bottom: 1px solid #1a1a1a;
  padding-bottom: 0.5rem;
}

.aside-title span {
  display: inline;
}

.aside-nav-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  counter-reset: aside-counter;
}

.aside-nav-list li {
  counter-increment: aside-counter;
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
}

.aside-nav-list li::before {
  content: counter(aside-counter, decimal-leading-zero);
  font-size: 0.7rem;
  font-weight: 700;
  color: #999;
  flex-shrink: 0;
  font-variant-numeric: tabular-nums;
}

.aside-nav-list li a {
  font-size: 0.82rem;
  line-height: 1.4;
  color: #1a1a1a;
  text-decoration: none;
  padding: 0.25rem 0;
  display: block;
  min-height: 40px;
  display: flex;
  align-items: center;
}

.aside-nav-list li a:hover {
  text-decoration: underline;
  text-underline-offset: 2px;
}

.aside-note {
  padding-top: 0.75rem;
  border-top: 1px solid #d0d0d0;
}

.aside-note small {
  font-size: 0.75rem;
  color: #888;
  line-height: 1.5;
}

/* ===== 页脚 ===== */
.site-footer {
  border-top: 1px solid #1a1a1a;
  padding: 1.5rem;
  text-align: center;
  background: #fdfbf7;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.4rem;
}

.footer-brand {
  font-size: 0.88rem;
  font-weight: 600;
  color: #1a1a1a;
  letter-spacing: 0.02em;
}

.site-footer small,
.footer-note {
  font-size: 0.76rem;
  color: #888;
  line-height: 1.6;
  display: block;
}

/* ===== 标题装饰 span ===== */
h2 > span,
h3 > span {
  display: inline;
}

/* ===== 区块分隔线辅助 ===== */
.content-body section + section {
  margin-top: 1rem;
  padding-top: 1rem;
}

/* ===== 响应式 ===== */
@media (max-width: 900px) {
  .wrap {
    grid-template-columns: 1fr;
  }

  .content-aside {
    position: static;
    order: -1;
  }
}

@media (max-width: 600px) {
  .site-nav {
    height: auto;
    flex-wrap: wrap;
    padding: 0.5rem 0;
    gap: 0.5rem;
  }

  .nav-left,
  .nav-right {
    flex: none;
    flex-wrap: wrap;
    gap: 0.1rem;
  }

  .brand-center {
    order: -1;
    width: 100%;
    padding: 0.4rem 0 0.2rem;
  }

  .nav-left li a,
  .nav-right li a {
    font-size: 0.72rem;
    padding: 0.5rem 0.4rem;
  }

  .hero-section {
    min-height: 60vh;
  }

  .hero-h1 {
    font-size: 1.8rem;
  }

  .hero-bg-text {
    font-size: 5rem;
    opacity: 0.5;
  }

  .site-main {
    padding: 2rem 1rem 3rem;
  }

  .content-body h2 {
    font-size: 1.2rem;
  }
}

@media (max-width: 375px) {
  .nav-left li a,
  .nav-right li a {
    font-size: 0.68rem;
    padding: 0.45rem 0.35rem;
  }

  .hero-h1 {
    font-size: 1.5rem;
  }
}

/* ===== prefers-reduced-motion ===== */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

button[aria-expanded]{min-width:44px;min-height:44px}